The present invention relates to a charging generator and, more particularly, to an improvement in the section for leading out an output terminal in a charging generator for use in a vehicle.
2. Description of the Related Art
Conventional charging generators of the type described above are disclosed in Japanese Utility Model Public Disclosure (Kokai) Nos. 61-171454 (1986), 61-41365 (1986) and b 62-149253 (1987). FIG. 4 shows the arrangement of the charging generator disclosed in Japanese Utility Model Public Disclosure (Kokai) No. 61-171454 (1986), while FIG. 5 shows the arrangement of the charging generators disclosed in Japanese Utility Model Public Disclosure (Kokai) Nos. 61-41365 (1986) and 62-149253 (1987). In FIGS. 4 and 5, the reference numeral 1 denotes a cup-shaped rear bracket, 2 a cup-shaped front bracket, 3 a rotary shaft which is supported through bearings 4 and 5 which are secured to the brackets 1 and 2, respectively, 6 a rotor, 7 a field coil, 8 a stator, 9a a front coil end, 9b a rear coil end, 10a a front centrifugal fan, 10b a rear centrifugal fan, 11 a brush holder, 12 a regulator, and 13 a heat sink of a rectifier.
In the output terminal lead-out section of the conventional charging genrator shown in FIG. 4, an axial output terminal 14 which is connected to the heat sink 13 of the rectifier is disposed so as to project axially outward from the side wall of the rear bracket 1 and rigidly secured together with an output terminal 16 by means of a nut 15. The output terminal 16 is extended radially along the outer periphery of the rear bracket 1 and the distal end portion of the output terminal 16 is projected in a direction which is substantially perpendicular to the axis of the rotary shaft 3 so that it is used to constitute a threaded portion 17. It should be noted that the output terminal 16 is covered with a resin material 18 in order to isolate the bracket 1 from the outside.
The output terminal lead-out section in the conventional charging generator shown in FIG. 5 is comprised of a connecting member 19 having one end thereof secured to the heat sink 13 of the rectifier and the other end thereof bent so as to extend axially and an output terminal bolt 20 which is in thread engagement with a threaded bore 19a provided in the second end portion of the connecting member 19 so as to extend perpendicular to the axis of the rotary shaft 3, the distal end portion of the bolt 20 projecting outward from the rear bracket 1.
As described above, it has been considered preferable to arrange the output terminal lead-out section of a charging generator such that the output terminal projects radially from the viewpoint of the space required to mount the generator on an engine, the arrangement of wirings and the efficiency of the mounting operation. The arrangement of the output terminal lead-out section is demanded to satisfy the following requirements:
(1) Since the output terminal which projects radially will interfere with the operation of automatically assembling the body of the charging generator, it must be capable of being mounted after the generator body has been assembled.
(2) It is necessary to minimize the number of required changes or modifications of the parts constituting the axial output terminal and the parts constituting the generator body.
(3) The terminal screw must be reliably locked from turning and the terminal base must have a satisfactorily high rigidity.
(4) The dimensional accuracy which is required to combine together the generator body and the terminal must be less rigorous.
(5) The contact resistance between the respective portions of the generator body and the terminal which are electrically connected together must be low.
(6) The production cost must be low and the overall size must be small.
The conventional charging generator shown in FIG. 4 suffers, however, from many problems. Since the electrically connected portion of the output terminal base needs knurling, it is necessary to mount the output terminal lead-out section in the process of assembling the generator body. Moreover, it is impossible to disassemble and reassemble the output terminal lead-out section. Further, since the distance from that portion of the terminal which is rigidly secured to the generator body to the threaded end portion of the terminal is long, the rigidity is low. In addition, the axial length is disadvantageously long, and since it is necessary to employ a split mold which consists of three mold members as a mold for forming the terminal base from a resin material, the production cost is increased.
The conventional charging generator shown in FIG. 5 also suffers from the following problems. When the external wiring is attached to or detached from the output terminal bolt, the bolt may be undesirably turned together with the wiring attachment which is screwed thereonto and therefore the thread engagement portions which are provided inside are likely to become loose. Further, since the structure is such that the output terminal bolt is in thread engagement with the connecting member or the heat sink with the circumferential wall of the bracket clamped therebetween, high positional accuracy is needed and it is also necessary to minimize the draft for the bracket which is generally made of an aluminum die casting alloy or it is necessary to machine the surface of the bracket to which the output terminal bolt is secured.